The present invention relates to a storage device, and more particularly to a technique that virtually assigns a plurality of storage devices into one memory area and provides the area to a computer.
There is known a technique called “virtualation,” which virtualizes a memory area available in a plurality of storage devices and provides the virtualized memory area as one or a plurality of virtual memory areas to a computer. A storage device is usually constructed with disk arrays. The disk array known as a Redundant Arrays of Independent Disks (RAID) and is a memory device where many disk drive devices are configured in arrays. Details of the disk array are described in: “A Case for Redundant Arrays of Inexpensive Disks (RAID).”
In addition, Japanese Patent Laid-open No. 6-161837 discloses a technique wherein, at the time of assigning a file to a user of a memory area available in a memory device, a storage device will automatically select a memory area that is optimum for assigning files, based on file attributes or file information such as type of space assignment.